I'm confused with these prepositions:
I lie under a stary night.
I lie underneath the skyline.
There are caves under the bround.
There are caves underneath the ground.
There are caves beneath the ground. (this is wrong)
Is there any possible rules I can use to explain to students?[/quiote]
The prepositions "beneath", "underneath", and "under" are synonyms. In most cases, they can be used interchangeably. There are some idioms and pat phrases that do not allow substitutions, however. If there are any differences, they would be mostly with the "unders",
IMO. I wouldn't use "under" or "underneath" unless what was I was "under (neath)" was actually over me. I would use "beneath" (or below) for things that are higher than I, but not directly over me. For example, I could walk "beneath" the trees without having tree limbs directly over my head. But I would only use "under" and "underneat" if the tree limbs were actually over my position.
One can't lie under a night of any kind. It is also not idiomatic to lie under a skyline.
All three of your cave examples work for me. :wink: